<!--
     Any copyright is dedicated to the Public Domain.
     http://creativecommons.org/publicdomain/zero/1.0/
-->
<svg xmlns='http://www.w3.org/2000/svg' width='100px' height='100px'>
  <!--
    A basic test for the <feDiffuseLighting> filter primitive.
    Setting kernelUnitLength on the <feDiffuseLighting> should allow us to
    assume pixel perfection.
    -->
  <filter id='f' x='0' y='0' width='1' height='1'>
    <feDiffuseLighting kernelUnitLength='1'>
      <feDistantLight/>
    </feDiffuseLighting>
  </filter>
  <path d='M0,0 h100 v100 h-100 z M20,20 v60 h60 v-60 z' filter='url(#f)'/>
</svg>
